Method, device and arrangement for measuring the dynamic behavior of an optical system

ABSTRACT

The invention relates to a method for measuring the dynamic behavior of an optical system. The aim of the invention is to render the dynamic behavior of an optical system objectively detectable. To this end, the optical system to be measured is stimulated by stimuli whereby causing it to react, and the reaction is detected by means of a wave front analysis.

The present invention relates to a method, device and arrangement formeasuring the dynamic behavior of an optical system.

Analysis of optical wavefronts of imaging and laser systems has becomeincreasingly important because it is the starting point for improvingthe quality of these systems. The availability of commercialShack-Hartmann sensors (such as SCLA series, WavefrontSciences,http://wavefrontsciences.com) allows aberrations to be detected veryaccurately and classified in the form of Zernike polynomials ofdifferent orders, or alternative representations.

Higher aberrations can also be measured using other aberrometers,including those according to the Tscheming principle, according to Abbe,or the Tracey (ray-tracing) aberrometer, or systems according to theskiascope principle.

Systems that are equipped with a CCD chip for storing the relevantoptical information, such as Shack-Hartmann sensors, allow dataacquisition to be carried out with video image frequencies, thusenabling dynamic processes to be recorded at a sufficient rate.

There are known methods for correcting also the higher aberrations ofthird order and higher according to the Seidel or Zernikeclassification, these methods going beyond the normal sphericalcorrection and cylindrical correction of aberrations. These methods use,for example, adaptive optics, which act in reflection as deformablemirrors, or liquid crystal optics acting in transmission. These adaptiveoptics are technologically complex and presently not yet fully developedin all aspects. At present, these optics achieve two-dimensionalresolutions of typically several square millimeters, and are alreadyused under laboratory conditions in closed-loop methods to influencewavefronts between the wavefront measurement and the adaptive element(see Fernández, E. J. Iglesias, I., Artal, P. “Closed Loop AdaptiveOptics in the Human Eye”, Optics Letters, Vol. 26, No. 10, May 15,2001). These systems have not been used so far besides and beyond themere correction of aberrations to carry out real dynamic analyses whilevarying the most different visual conditions.

Furthermore, especially for ophthalmologic applications, methods havebeen shown by which wavefronts that are deformed by the optical systemof the eye are corrected to an ideal value by integrally taking intoaccount higher-order aberrations (see Optics Letters, Vol.

No. 4/Feb. 15, 2000, 236-238, AWACS—Asclepion Wavefront AberrationCorrection Simulator—a company document for presentation at the ESCRS inBrussels, September 2000 and at the AAO in Dallas, October 2000).

It is therefore an object of the present invention to provide a method,device and arrangement for objectively determining the dynamic behaviorof an optical system.

This objective is achieved by a method for measuring the dynamicbehavior of an optical system, in which the optical system to bemeasured is stimulated to respond, and the response is determined by awavefront analysis.

The dynamic behavior of the optical system encompasses, in particular,processes of adaptation to changed visual conditions, for example,accommodation or aperture adjustment (adaptation). The optical systemmay be an eye, such as a human eye, an artificial eye, or any otherartificial device. The stimulus may, in principle, be of any nature. Theresponse is the dynamic behavior of the optical system following thestimulus. The wavefront analysis may be carried out using anaberrometer, in particular, using Shack-Hartmann sensors, but also usingaberrometers according to the Tscheming principle, according to Abbe,with a ray tracing aberrometer, or a system according to the skiascopeprinciple. In the case of accommodation, it is possible, in particular,to determine the current focus at any one time as well as its variationover time. It is also possible to determine different iris adjustmentsin terms of their variation over time. In this connection, the dynamicbehavior may also be examined, for example, under the influence ofmedication.

One embodiment of the method proposes that the stimuli be visual and/ormechanical and/or electrical and/or chemical stimuli. Variable visualstimuli may be produced, for example, using actively controllable lightsources, illuminated representations, or the like. In particular, thesharpness of the image and/or the object distance and/or the focusthereof and/or the intensity of the visual stimulus may be varied so asto cause the optical system to undergo accommodation or iris adjustment(adaptation). An aberration of even higher order, for example, in theform of a suitably “deformed” object wavefront may also be used as thevisual stimulus. Variable mechanical stimuli may be produced, forexample, as an air draft using a blower. Variable chemical stimuli maybe produced, for example, by smoke or by introducing a liquid, a gas, oran aerosol. Administration of medication is also possible. Variableelectrical stimuli may be achieved using electrodes applied directly tothe eye or in the area of the eye, or by an electrical signalinductively or capacitively coupled in. The above-mentioned stimuli maybe applied alone or in any combination, and be varied either abruptly orcontinuously.

In one embodiment of the method, the optical system to be measured is ahuman eye. It is an aim of the method aims to stimulate an individualeye or the eye system in the visual process in order to selectivelyproduce an excitation and an associated influence on the eye parameters.The induced changes in the eye parameters directly change the imagingproperties of the eye and are therefore accessible, for example, via awavefront measurement triggered synchronously with the excitation. Thismethod allows analysis and measurement of the most different effects.For example, the time dependence and speed of accommodation and of theaccommodative capacity, the adaptation and adaptive capacity oradaptation speed of the eye may be examined under influences such asaberration, illumination, medication, or psychic influences. The dynamicshort- and long-time behavior of contact lenses, such as slippage or thelike, may be examined with respect to the changes in aberration due towearing of contact lenses. It is possible to determine the dynamicbehavior of intraocular lenses (IOL) and accommodative intraocularlenses, and the reciprocal effect of the residual ciliary body onintraocular lenses, as well as the fit and movement and, possibly, theinduced accommodation thereof. Also possible are connections between thephysical vision and the brain performance which may possibly helpdiscover objective conclusions about clinical pictures such as headachesdue to overstress. Thus, for example, it is possible to measure dazzlingeffects and other time-variant effects in connection with fatiguephenomena during motoring. Dynamic optical correction may be examined,for example, in relation to occupational groups, i.e., in terms ofspecific visual requirements.

In a refinement of the method, it is proposed to synchronize thestimulation of the eye to be measured with the aberrometer. This allowsthe measured adaptation processes of the eye to be directly associatedwith the particular stimulus and its variation over time. In theprocess, the synchronization can be carried out, for example, temporallyor with respect to the intensity between the particular stimulus and theaberrometry measurement.

When carrying out the method, it is possible to stimulate one or both ofthe human eyes to respond. Similarly, it is possible to measure one orboth of the human eyes. Based on the dynamic measurement resultsobtained by stimulation, optimized/averaged values for static/stationarycorrection of the wavefront may be derived for the specific eye that hasbeen measured. This makes it possible to provide the eye with an optimalwavefront correction for its specific action spectrum. It is alsopossible to provide solutions tailored to specific visual processes.Examples to be mentioned include night vision, speed-optimizedaccommodation, or close and distant vision.

The objective mentioned at the outset is also achieved by a device formeasuring the dynamic behavior of an optical system, in particular, of ahuman eye, including a stimulation unit and an aberrometer. Using thestimulation unit, the optical system to be examined may be selectivelycaused to adapt to external stimuli. For this purpose, the stimulationunit is designed such that it can exert these external stimuli on theoptical system. Possible external stimuli include, in principle, allphysical or chemical effects or means that produce an adaptive responseof the optical system. The stimulation unit may act on the opticalsystem abruptly and/or continuously, and be disposed in front of eitherthe unmeasured optical system or the optical system to be measured.Here, “aberrometers” are generally understood to mean devices forwavefront measurement or aberration measurement. These may include bothdevices with electronic data acquisition and manually operable devices.

A particularly simple and, moreover, automated way of evaluating theoptical data is possible if the aberrometer includes a wavefrontanalysis device. The wavefront analysis device may be, for example, aShack-Hartmann sensor equipped with a CCD chip for storing the relevantoptical information.

The measurement results, and thus the result of the dynamic adaptationprocess, may be graphically visualized by transferring the data to asoftware application.

It is particularly advantageous if the stimulation unit is able totrigger a visual and/or mechanical and/or electrical and/or chemicalstimulus. In particular, a visual stimulus may be designed to cause theoptical system to undergo accommodation or iris adjustment. Thus,different stimuli may be exerted on the eye, thus also allowingsimulation of everyday situations, such as an air draft or chemicalstimuli caused by smoke, or the like.

The stimulation unit may be disposed in front of the eye that looks pastthe aberrometer or, alternatively, the beam path of the stimulation unitmay be reflected into the aberrometer. In the first-mentioned embodimentof the device, the eye not to be examined may be stimulated whereas inthe second-mentioned embodiment, the eye to be examined may be directlystimulated by external stimuli.

Alternatively, the stimulation unit may be integrated into theaberrometer. In this case, the beam path of the stimulation unit isdirectly coupled into that of the aberrometer in a common housing. Thisenables a very compact design.

The device may be designed for both monocular and binocular vision.Similarly, the stimulation may affect one or both eyes. Therefore, eyemeasurement and eye stimulation may be implemented in any combination,for example, stimulation of one eye and measurement of the other eye,stimulation of one eye and measurement of the same eye, stimulation ofone eye and measurement of both eyes, stimulation of both eyes andmeasurement of one or both eyes.

In a preferred embodiment, it is proposed that the stimulation unitinclude a fixation object. The subject has to fixate the fixationobject, thus causing the eye to focus in a defined manner. The fixationobject is a pictorial representation that is easily recognizable by thesubject, or a defined light spot. Here, it is preferred to use a finelypatterned image, or a light source composed of a plurality of elementswhich may, for example, be graduated in color.

It is advantageous if the fixation object is able to emit a lightstimulus that is variable in intensity and/or focus. The eye focusingthe fixation object may be stimulated directly in this manner. Thechange in intensity may be achieved, for example, by changing theluminosity when using light sources as the active elements, or bychanging the illuminance when using passive elements such as anilluminated graphic. A change in focus is possible, for example, bymoving the fixation object itself, or by changing lenses disposed infront thereof.

The fixation object is preferably an illuminated graphic. This is anobject which can be easily and reliably recognized and fixated by thesubject and which, moreover, is easy to implement.

The device may include at least one phase plate that is insertable intothe beam path of the stimulation unit and/or of the aberrometer.Advantageously, a set of phase plates is used, which are sorted by thedifferent Zernike polynomials with graded amplitudes, and which may bepositioned in front of the system to be examined, similarly to the triallenses in the known phoropter. Possible phase plates include, forexample, transparent glass or plastic plates whose surfaces arepatterned in such a manner that defined aberrations, for example,according to a single Zernike term, are superimposed on a light wavethat passes through the plate. A changing device, preferably a turretchanger, preferably contains plates of one order of the Zernikecoefficients with different amplitudes. By providing several suchchanging devices one behind the other in a centered arrangement, it ispossible to rotate different phase plates into the optical visual axisof the optical system to be examined. Thus, a finely gradablecombination of higher-order aberrations may be placed on the opticalvisual axis of the optical system to be examined. This arrangementallows, in particular, visual defects that are due to higher-orderaberration to be subjectively assessed after an adapted stationarystate, for example of the human eye, has been reached. The assessmentmay be carried out using a time scale, for example, after severalseconds of adaptation.

The device may include software for evaluating the differentlystimulated dynamic measurement data of the eye, the software providingan optimal or average wavefront value, which is used forstatic/stationary correction of the optical defects of vision in theknown correction methods (spectacles, CL, IOL, LASIK, PRK, . . .)

The objective mentioned at the outset is also achieved by an arrangementfor measuring the dynamic behavior of an optical system, in particular,of an eye, including an aberrometer and a stimulation unit. In thisarrangement, the elements previously implemented together in the deviceare separated. Therefore, it is also possible to use a conventionaldevice for measuring the aberration of an eye together with anindependent stimulation unit. The objective mentioned at the outset isalso achieved by the use of a device according to one of the claims thatare directed to a device for measuring the dynamic behavior of anoptical system.

Advantageous embodiments of the present invention will be furtherexplained with reference to the drawing, in which

FIG. 1 is a schematic diagram of a device for carrying out the method;

FIG. 2 is a schematic diagram of a first embodiment of the deviceaccording to the present invention;

FIG. 3 is a schematic diagram of a second embodiment of the deviceaccording to the present invention.

Reference is first made to FIG. 1, which is a schematic diagram of adevice and the associated method sequence for dynamic stimulation anddynamic measurement of the aberrometry of an eye 15. The Figure showsthe individual components and their operative connection. The deviceincludes a unit for measuring the wavefront/aberrometry of eye 15, theunit being able to measure either both eyes at the same time or one eyeat a time. In the latter case, the eye that is currently not beingmeasured, may either look with an unrestricted view past the unit, oralso look into the unit. For the sake of simplicity, the unit formeasuring the wavefront/aberrometry of an eye will be referred to as“aberrometer 1” hereinafter. Aberrometer 1 emits measurement light 16into eye 15, and the eye returns signal light 17. Measurement light 16and signal light 17 are indicated by arrows in FIG. 1. The devicefurther includes a device for dynamic data acquisition 2 which receivesraw data 19 of aberrometer 1. This further device may be a common devicefor measurement value acquisition, such as a program-controlled computerincluding software capable, in particular, of acquiring sequentialseries of measurements in real time. For this purpose, intermediate datastorage may be required in a volatile or non-volatile memory, forexample, of a control computer. The device further includes analysissoftware capable of analyzing the acquired data or data sets in order tocalculate the determining parameters of the wavefront (for example,Zernike or Taylor coefficients). The measurement results, and thus theresult of the dynamic adaptation process, may be graphically visualizedby a software application. For this purpose, an analysis module 3 isused to which the acquired data is transferred. The capabilities ofdynamic data acquisition 2 and of analysis module 3 may be combined insuch a manner that a sequential real-time measurement with simultaneousanalysis can be carried out that is adapted to the hardware and possiblyreduced in its acquisition rate. Also provided is a stimulation unit 4for producing an optical influence, for example, aberration, lightinflow, object distance, or the like, in an abruptly and/or continuouslyvariable manner. This stimulation unit is disposed in front of eitherthe unmeasured eye 15 or the eye 15 to be measured, and may besynchronized with dynamic data acquisition 2. The stimulation of eye 15is indicated by an arrow 18 in FIG. 1. A synchronization unit 5 is usedfor synchronization between stimulation unit 4 and aberrometer 1. Thesynchronization unit may send synchronization pulses 20 (indicated bydashed arrows in FIG. 1) to the aberrometer and/or the device fordynamic data acquisition 2.

Stimulation of eye may also be accomplished using eye charts and thelike without the need for synchronization. Thus, the connection betweenstimulation unit 4 and aberrometer 1 and/or dynamic data acquisition 2is thus dispensed with. Aberrometer 1, dynamic data acquisition 2,analysis module 3, and stimulation unit 4 may also be implemented as aunit and thus as a one-part assembly.

Stimulation unit 4 may also be implemented and used as an independentseparate unit. The then existing unit is kind of a stimulation phoropterthrough which the subject may assess, for example, a phase-platecorrection with or without variation of other visual parameters.Synchronization unit 5 may then be dispensed with.

FIGS. 2 and 3 show specific embodiments of the device. The shown beampaths through a first lens 6, a second lens 7, and a third lens 8 do notexactly correspond to the real beam paths when considered within theframework of geometrical optics, but are only intended for purposes ofillustration. The practical implementation of the optical concept may beaccomplished in such a way that the patient's nose does not constitutean obstacle. In the optical set-up shown in FIGS. 2 and 3, a phase plate9 is located in a plane conjugate to the corneal surface or spectaclecorrection surface. By integrating a mechanism (not shown) forautomatically changing phase plates 9, for example, in the form of aphase-plate changer wheel or the like, it is also possible to easilyproduce different aberrations during or between measurement series. Afirst iris 10 and a second iris 11, together with the fixation at afixation object 12, define the optical axis. Further aiming devices,such as surface crosses, may also be provided, as the case may be. Inaddition, the centration may be checked by a video image which may bepicked off, for example, by beam splitters inside the device of FIGS. 2and 3. Varying accommodation states may be stimulated by moving thefixation object along a travel path 13, or alternatively, for example,by moving third lens 8. The adaptation may be influenced throughadjustment of the illumination of fixation object 12 by a light source14. Additionally or alternatively, it is possible to directly adjustbrightness of the room light and/or of the ambient light. This option isnot shown for the sake of simplicity. The individual components may becontrolled and actuated electrically or electromotively. Thesynchronization of these components with the measurement and the dataacquisition may then be easily carried out by querying programmableinterfaces.

In the device according to FIG. 2, eye 15 is measured, and therespective other eye 15 is stimulated, while in the device according toFIG. 3, the eye 15 to be measured is stimulated at the same time. First,the common set-up in FIG. 2 will be explained. The device includes anaberrometer 1, which is a unit for measuring the wavefront deformationby the optical system of the eye and thus for determining andclassifying the aberrations of eye 15, including also higher-orderaberrations. Aberrometer 1 is coupled to a device for dynamic dataacquisition 2 which here is a module for controlling aberrometer 1. Thismodule may trigger a wavefront measurement process. It is also possibleto store the acquired measurement data intermediately, and tosubsequently reconstruct the measured wavefront from the measurementdata. For this purpose, it is possible to store, for example, the rawdata of the video image of the sensor, or also completely evaluatedwavefront parameters such as Zernike coefficients. The measurement andpossible evaluation and storage are carried out at clock rates that arefaster than the adaptation process to be examined. The clock rates may,for example, be in the range of 10 to 100 Hz.

The device for dynamic data acquisition 2 is coupled to an analysismodule 3. Analysis module 3 is used for evaluation of the sensor dataand, possibly, for reconstruction and graphical visualization of themeasured and stored wavefronts, and may substantially be implemented insoftware. Moreover, it is possible to parameterize the wavefront, forexample, through expansion by Zernike polynomials, or by zonalreconstruction. The analysis process may be coupled in close couplingwith the device for dynamic data acquisition 2, and perform the analysisprocess partially or completely before intermediate storage.

A stimulation unit 4 is essentially composed of an optical system whichpresents to the eye 15 to be examined or to the free eye 15 a visualobject to be fixated which has a defined pattern, and which induces eye15 to focus on the pattern of the object. Stimulation unit 4 may containoptical elements, such as lenses or phase plates, which deform thewavefront originating from the visual object before it enters the eye.Eye 15, which tries to obtain a sharp image of the visual object, maythus be stimulated to undergo adaptive responses within the opticalsystem. Preferably, the imaging properties of stimulation unit 4 may bevaried over time to produce a dynamic response of eye 15. Stimulationunit 4 may send information about its current state to a synchronizationunit 5 with the wavefront measurement.

Synchronization unit 5 is a module for synchronizing dynamic changes instimulation unit 4 with the device for dynamic data acquisition 2. Theaim is to correlate the measured wavefront data with the respectivestates of the synchronization unit.

The embodiments of an aberrometer 1 shown in FIGS. 2 and 3 may bereferred to as “dynamic stimulation aberroscopes”. Here, it should benoted that the optical concept may be implemented in such a manner that,unlike in the diagram, the unmeasured eye does not have to be restrictedin its view, but may look with an unrestricted view. In a simplifiedvariant, it would be possible to dispense with the synchronizationbetween stimulation unit 4 and aberrometer 1 and device for dynamic dataacquisition 2. In further variants, an eye chart that is stationary ormovable for varying the distance and/or a phase-plate phoropter are usedfor stimulation instead of an integrated fixation object.

The embodiment of a stimulation unit 4 shown in FIG. 2 is also to beregarded as an improvement to the simple phase-plate phoropter, and maybe designed as a stand-alone device to include, for example, correctionof the aberration and a simple eye chart as the fixation object, etc.,in the different variants.

To selectively superimpose aberrations on the object wavefront, it isoptionally possible to insert an adaptive optical element instead of aphase plate and/or the imaging optics according to FIGS. 2 and 3. Thethereby stimulated dynamic changes in the imaging properties of eye 15are dynamically determined by aberrometer 1 in a time sequence which maybe synchronized with the variation of the imaging properties by theadaptive optics. Transmission-based adaptive elements, such asliquid-crystal phase modulators, may be mounted in the arrangementaccording FIGS. 2 and 3 instead of, for example, the phase plate in asimilar manner.

Although the use of an adaptive optic additionally requires anelectronic control of the adaptive optic and is therefore morecomplicated, it offers stimulation options which would not be possible,or only with difficulty, using devices with phase plates. Depending onthe control speed of the adaptive optical elements, it is possible todynamically change or to selectively apply arbitrary aberrations of theobject wavefront.

Stimulation unit 4 is designed as an optical system which is placedeither in front of the eye 15 that is unrestricted in its view, or isreflected into the beam path of the eye examined by the aberrometer, asshown in FIG. 3, or stimulation unit 4 is integrated into aberrometer 1.In the case of the latter embodiment, again, two variants are possible:stimulation unit 4 may act on the measured eye or eyes 15, or on theunmeasured eye 15.

The stimulation unit itself is an optical device, in which a fixationobject is placed in front of the measured eye or eyes, or the eyes thatare unrestricted in their view, and whose center is to be fixated andfocused by the respective eye during the examination. The optical actionduring stimulation may be modulated either abruptly or continuously,which is achievable, for example, by changing the distance, luminanceetc., of the fixation object, and/or by mounting phase plates. Alloptically effective modifications may be combined in any way. If theoptical action is synchronized, for example, in terms of time orillumination, with the dynamic measurement of eye 15 by aberrometer 1,then the devices embodied according to FIGS. 2 and 3 are obtained.Synchronization of the action is not necessarily required. Informationabout the dynamic responses of the eye or eyes may also be measured inan unsynchronized manner. To this end, it is possible to associate themeasured values temporally, for example, via the knowledge of the dataacquisition frequency of the device for dynamic data acquisition 2. Themeasured values may be provided with a time stamp, for example, whenelectronically stored on a data carrier or the like. The device fordynamic data acquisition 2 and analysis module 3 may also be combined soas to perform not only dynamic data acquisition, but at the same timealso high-speed analysis of the data.

Fixation object 12 may be implemented, for example, by an illuminatedgraphic having a sufficiently fine pattern, but may also be a simple eyechart positioned separately.

The imaging of fixation object 12 may be accomplished by swinging inoptical elements such as lenses, and may possibly be checked via a videosystem. The centration with respect to a predetermined line of sight maybe optimized by iris systems. For example, an automatic positioningmeans makes is possible to selectively produce accommodation states byvarying distances between the optical components and/or the fixationobject. Suitable adjustment of the illumination of the fixation objectand/or of the room light leads to defined adaptation adjustments, whichmay also be kept variable and which form additional measurementparameters.

By inserting specially prepared phase plates with defined surfacetopography into the beam path of stimulation unit 4 and/or ofaberrometer 1, the device allows aberrations to be selectively appliedto eye or eyes 15. To this end, the phase plates may be disposed in aturret changer (not shown here) and able to be inserted into the beampath of stimulation unit 4 and/or of aberrometer 1 individually or incombination.

The above-described device and the method which can be carried out withit are used for selective visual stimulation of a biological orartificial eye 15 and for determining the associated dynamic adaptationprocess of the optical visual apparatus by measuring the wavefrontaberration. The visual stimulation produced when viewing into or througha suitable apparatus produces an influence on the imaging properties ofeye 15; this influence being simultaneously measurable in real time andin time synchronization with the stimulation using a wavefront analysissystem or aberrometer 1. This enables completely new ways of diagnosis,making the dynamics of adaptation processes of eye 15 accessible. Tothis end, visual conditions, such as object distance and brightness aremodified and specific aberrations are selectively corrected and/orintroduced, in particular, simultaneously. This makes it possible, forexample, to study the influence of specific aberration terms on theaccommodative capacity, or to examine whether an implantable intraocularlens is capable of accommodation in virtue of the residual ciliary body,and how this may possibly be used in an optimal manner. A furtheradvantage of the present invention is that it allows personalimpressions of a subject during the assessment of dynamic visualprocesses to be correlated with physically objective measurement data.

Using the device and method, it is possible to stimulate dynamic changesin the imaging properties of the eye, and to record their variation overtime. A system of optical elements allows to selectively compensate forexisting aberrations of even higher order, and to selectively introduceother aberrations for stimulation to determine the influences on thedynamics of the optical system of eye 15. This allows the most differentdynamic processes, such as during accommodation or adaptation, to bedocumented in an image sequence or video recording of the development ofthe wavefront aberrations, from which it is possible to derive dynamicparameters, such as adaptation range, times, speeds, or accelerations,for example, during accommodation or adaptation. In this manner,conclusions about anatomical parameters, such as the elasticity of theeye lens, which may be connected, for example, with questions of theinteraction of the deformation of the eye lens and cornea and thedynamics of intraocular lenses, or also the primary response capacity ofthe eye, become objectively measurable. It is possible to discoverfundamental relationships of the effect of medication or, for example,cause-effect relationships of clinical pictures such as headaches,fatigue, and overstress.

The described invention allows objective dynamic measurement of theimaging properties of the eye during selectively stimulated adaptationprocesses under predefined boundary conditions.

List of Reference Numerals

-   1 aberrometer-   2 device for dynamic data acquisition-   3 analysis module-   4 stimulation unit-   5 synchronization unit-   6 first lens-   7 second lens-   8 third lens-   9 phase plate-   10 first iris-   11 second iris-   12 fixation object-   13 travel path-   14 light source-   15 eye-   16 measurement light-   17 signal light-   18 stimulation-   19 raw data-   20 synchronization pulses

1-18. (canceled).
 19. A method for measuring a dynamic behavior of anoptical system, the method comprising: stimulating the optical system toso as to elicit a response; and determining the response using awavefront analysis.
 20. The method as recited in claim 19, wherein thestimulating is performed using at least one stimulus selected from thegroup consisting of a visual stimulus, a mechanical stimulus, anelectrical stimulus, and a chemical stimulus.
 21. The method as recitedin claim 19, wherein the optical system includes a human eye.
 22. Themethod as recited in claim 20, further comprising synchronizing thestumulus using a wavefront analysis device.
 23. The method as recited inclaim 21, wherein the optical system includes a first eye and a secondeye of a human, and wherein the stimulating is performed on at least oneof the first and second eye, and wherein the determining is performed onat least one of the first and second eye.
 24. A device for measuring adynamic behavior of an optical system, the device comprising: astimulation unit; and an aberrometer.
 25. The device as recited in claim24, wherein the optical system includes a human eye.
 26. The device asrecited in claim 24, wherein the aberrometer includes a wavefrontanalysis device.
 27. The device as recited in claim 24, wherein thestimulation unit configured to trigger at least one stimulus selectedfrom the group consisting of a visual stimulus, a mechanical stimulus,an electrical stimulus, and a chemical stimulus.
 28. The device asrecited in claim 24, wherein the optical system includes a first eye anda second eye of a human.
 29. The device as recited in claim 28, whereinthe stimulation unit is disposed in front of the first eye while thefirst eye is looking past the aberrometer.
 30. The device as recited inclaim 28, wherein a beam path of the stimulation unit is reflected intothe aberrometer.
 31. The device as recited in claim 28, wherein thestimulation unit is integrated into the aberrometer.
 32. The device asrecited in claim 24, wherein the stimulation unit includes a fixationobject.
 33. The device as recited in claim 32, wherein the fixationobject is configured to emit a light stimulus that is variable in atleast one of an intensity and a focus.
 34. The device as recited inclaim 32, wherein fixation object includes an illuminated graphic. 35.The device as recited in claim 24, further comprising at least one phaseplate insertable into a beam path of at least one of the stimulationunit and the aberrometer.
 36. An arrangement for measuring a dynamicbehavior of an optical system, the arrangement comprising: anaberrometer; and a stimulation unit.